RFR: 8271939: Clean up primitive raw accessors in oopDesc [v2]

[Roman Kennke]

> We have some _raw accessors in oop.hpp and related code. Those are leftover from when Shenandoah required primitive barriers and are no longer needed. Their uses can be replaced with the regular accessors.
> 
> Testing:
>  - [x] tier1
>  - [x] tier2
>  - [x] hotspot_gc

Roman Kennke has updated the pull request incrementally with one additional commit since the last revision:

  Change loader_data_raw() to regular loader_data()

-------------

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/5017/files
  - new: https://git.openjdk.java.net/jdk/pull/5017/files/12b3c772..515c3a8a

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=5017&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=5017&range=00-01

  Stats: 6 lines in 4 files changed: 0 ins; 0 del; 6 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5017.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5017/head:pull/5017

PR: https://git.openjdk.java.net/jdk/pull/5017